On 02/01, Oleg Nesterov wrote: > > However, shouldn't this patch also remove the comment which explains > the possible lock inversion? Above put_pid(), > > /* > * Note: disable interrupts while the pidmap_lock is held as an > * interrupt might come in and do read_lock(&tasklist_lock). > * > * If we don't disable interrupts there is a nasty deadlock between > * detach_pid()->free_pid() and another cpu that does > * spin_lock(&pidmap_lock) followed by an interrupt routine that does > * read_lock(&tasklist_lock); > * > * After we clean up the tasklist_lock and know there are no > * irq handlers that take it we can leave the interrupts enabled. > * For now it is easier to be safe than to prove it can't happen. > */ Ah, sorry, please forget, you did it in the previous patch. which probably needs some more discussion... Oleg.
